Thomas Tuchel insists he cannot have a preferred starting XI at Chelsea.
The Blues' German boss became the first manager to register clean sheets in all of his first five Premier League home matches, as Chelsea saw off Everton 2-0 on Monday.
Ben Godfrey's own goal and Jorginho's penalty extended Tuchel's unbeaten start at Chelsea to 11 matches, with the Blues cementing fourth place in the Premier League table.
Tuchel made five changes and tweaked Chelsea's system to face the Toffees, despite Thursday's 1-0 win at Liverpool – and revealed that tactical fluidity as crucial to his managerial method.
"If you play in competitions like the Premier League, Champions League and FA Cup there's no way that you arrive with 11 players in your head," said Tuchel.
"First of all whoever you see on the pitch deserves to be on the pitch.
"And we need to analyse what we give there, we cannot just keep players on the pitch to keep them going.
"After two intense games, away games, where we'd missed a lot of sleep in travel, it was the moment to change against Everton.
"I had no doubts about that, because the guys on the pitch deserved to be there.
"We expected a bit of a man-marking midfield and we went for speed and deep runs today.
"Sometimes the changes are tactical decisions, whereas for Kurt Zouma he deserved his chance and Toni Rudiger needed a little break, having been outstanding in terms of both performance and concentration.
"So there's a reason for every change. We did not lose quality at all and everybody feels we can play on a high level."
Kai Havertz thrived in a new role as a false nine, producing his best moment in a Chelsea shirt since his £70million summer switch from Bayer Leverkusen.
Havertz was unlucky to end the night without a goal, but won the penalty that Jorginho converted.
Callum Hudson-Odoi impressed greatly in his natural left-wing role, creating the opening goal and threatening throughout.
Chelsea's immediate fluidity in attack despite a new system underscored Tuchel's ability to switch tactics without much time on the training ground and augurs well for the campaign's business end.
Christian Pulisic has struggled to impose himself so far under Tuchel and featured only as a last-gasp replacement against Everton.
Tuchel admitted Pulisic has been one of the early fall guys in his Chelsea reign, with the USA forward so useful as an impact substitute.
"I cannot say anything other than good things about him," said Tuchel.
"Maybe his problem is I know from Dortmund how strong he is from the bench.
"He started only in the cup game. It's my responsibility and my fault, but it's a bit unfair because I know how good he is and what impact he can have in 20, 30 minutes.
"So there's no lack of trust, no lack of quality, he just needs to be a bit patient."
Everton's first defeat in four matches could prove a hammer blow to their chances of a top-four finish, but boss Carlo Ancelotti insisted that had never been his target.
"I think that honestly we never talked about the top four," said Ancelotti.
"If we are in the top four fantastic, but we want to be top six, top seven, to play Europe next season.
"This defeat doesn't change that we are in the fight. We have more chances to take."
